Bi 400

  • Sale
  • $ 799

The long-awaited 400 watt bass amplifier from Form Factor Audio. Next-generation solid-state preamp and a true 400 watt module deliver unparalleled tone, sound clarity and response. MADE IN USA.


Putting out 400 REAL watts at 4Ω, the Bi 400 outperforms the competition when it comes to palpable tone, power and headroom. The smaller, lighter version of the Bi 1000 shares every component with its bigger brother, except for the Class D amp module, so the sound is the same, but with a different power output.

Ideal for live work, the studio and rehearsals, the Bi 400 puts out serious SLP and can be pushed to surprising output levels without losing its signature tone or breaking up or clipping.

As with the Bi 1000, the Bi 400 has our state of the art pre-amp, which was designed from the ground up to deliver the type of clarity, response time and tone that you’ve never heard from an amp this size. It lets you hear the bass the way it was meant to be heard, by enhancing the characteristics the luthier intended the instrument to have.

Hand built in California, featuring genuine Neutrik and Amphenol connectors and aerospace-grade chassis materials, the Bi 400 is high-end enough to be precious with, but tough enough to survive years and years of gigs and rehearsals.



  • Model: Bi 400
  • Configuration: 1 x 400 Watts | Class D Amplifier
  • Power Rating: Power 400 Watts RMS @ 4Ω | 250 Watts RMS @ 8Ω
  • IN/OUT: Active| Passive | Tuner | Send | Return | Amp Direct | Balanced Direct Out | 2 x Speaker Out
  • Connectors: 2 x NL4 Speakon™ | 1 x Powercon™ | 6 x Neutrik 1/4″ | 1 x Balanced XLR
  • Finish: Powder Coated Steel
  • Finish Color: Black
  • Controls: Gain | Limiter | Master | Mute
  • Tone Controls: Bass | Mid | Mid Frequency Selector | Treble
  • Weight: 6Lb | 2.7Kg